By Mark N. Charrette, DC
We are all familiar with “The Skeleton Dance” song lyrics, “The foot bone’s connected to the leg bone; the leg bone’s connected to the knee bone,” and so on. In this article, I will discuss the importance of analyzing, appropriately adjusting, and stabilizing the feet, knees, and hips so that our spinal adjustments have the greatest effect and last longer.
When we’re weight-bearing or functional, the major focus of the motor output of our nervous system is to look at Earth’s horizontal plane.1,2 The body will adapt mechanically in somewhat predictable ways to achieve that. The greatest distortion in the lower extremity is visualized at the part of the gate cycle known as midstance, where the heel and toes are in contact with the ground or surface.
The Feet
Most adults develop an excessive or hyperpronation of the feet.3 This is usually asymmetrical, with the greatest pronation occurring on the superior ilium/long side.4 The superior-to-inferior measurement decreases when the foot pronates, hence a flatter foot. This appears to be a developmental manifestation that can help level the pelvis and, ultimately, the shoulders and head since equilibrium is a primary focus of the functional posture.
A tri-planar motion involving eversion, dorsiflexion, and abduction at the subtalar joint occurs when the foot pronates. This, in turn, will cause a decrease in the height of the three arches of the feet when weight-bearing.
In the pronated foot, the bones of the feet misalign/subluxate in a predictable pattern. Compared to the neutral foot, the navicular misaligns/subluxates in an inferior and medial direction. All three cuneiforms are inferior — the cuboid, superior, and lateral. The talus is predominantly anterior and slightly lateral. The second, third, and fourth metatarsal heads are inferior, while the calcaneus will plantar flex and evert. The problem with adjustments of the feet is that the foot returns to essentially the same position after the patient is adjusted and walks several steps.
The reason that occurs is because significant support for the arches and other joints in the feet is ligamentous in nature.5,6 The ligamentous soft tissue support for the three arches of the feet (medial longitudinal, lateral longitudinal, and anterior transverse) undergoes a long-term process known as plastic deformation.
The average adult takes 7,000 to 10,000 steps per day, and in a walking gate, each heel strike is two-and-a-half times body weight (in a running gate, it is three-and-a-half times body weight). Over time, the plantar fascia and many other bone-to-bone ligaments, such as the spring ligament, will plastically deform, causing the foot to be less stable. Compared to the same foot “nonpronated,” a pronated foot is more expansive, longer, and flatter due to the decrease in the foot’s three arches.
As I see it, idle foot support during the weight-bearing gate cycle:
Allows for the optimal or normal ranges of motion of the foot.
Supports all three arches of the feet (medial longitudinal, lateral longitudinal, and anterior transverse.
Has an arch height that allows optimal/normal ranges of motion to occur.
Still, excessive motions such as pronation are blocked (this will be discussed further later in the article).
In a 2017 issue of The Archives of Physical Medicine and Rehabilitation, the results of a randomized control study utilizing a three-arch functional foot orthotic as previously described showed:
A reduction in low back pain by 34.5%.
Foot orthotics used alone or in conjunction with chiropractic care improve function by 18.5% and 32.3 %, respectively.7
The Knees
In my observations and analyses of knees, it appears that knees at midstance are usually internally rotated, placing excessive stress on the medial meniscus, anterior cruciate ligament, and medial collateral ligaments. This led to the term “unhappy triad” for the knee.
I find that the condyles of the knees will be in a rotational or posterior misalignment/subluxation pattern. Based on the palpatory/motion indicator, the appropriate adjustment should be administered to the knee(s) to increase/restore optimal ranges of motion.
The Hips
Femur heads also follow a predictable pattern with an internal rotation distortion. For most low back pain patients, motion palpation shows restriction of external rotation in the femur heads. Again, appropriate adjustment/mobilization will optimize motion in the hip joint.
The neurological aspect of lower extremity adjusting and stabilization is not often talked about. When joints fixate/misalign/subluxate a joint complex, dysfunction occurs. Following is a brief synopsis of at least two things chiropractors facilitate neurologically in patients when adjusting.
The first drives most of our patients to us — pain and symptomatology.
The hypomobility/fixation/subluxation that occurs in any joint causes the type 1, 2, and 3 mechanoreceptors to decrease their firing rate, which causes an increase in the firing of the type 4 mechanoreceptors/nociceptors.
If the nociceptive impulses are of an intensity strong enough to reach the threshold in the sensory cortex, the sensation of pain will be felt. Most nociceptive impulses fail to reach the threshold; pain thresholds are relatively high.8,9,10
What else do nociceptors do? Cumulatively, they reflexively activate the sympathetic nervous system, triggering the fight-or-flight mechanism to some degree. This response causes changes in physical indicators, such as heart rate, blood pressure, respiratory rate, and even cortisol levels. This process is sometimes known as dysafferentation.11,12
Any amount of restricted range of motion in any joint will cause an increase in nociceptor firing. This occurs cumulatively.
Therefore, I think there is great value in examining joints that may or may not be symptomatic for indicators, of which restricted range of motion is a significant indicator, and then performing the appropriate adjustment. If the indicator changes, the chiropractor knows the procedure has had an effect.
When motion is increased in any joint, nociception will always decrease. This is why, in general, patients presenting in our offices are more hypertonic and symptomatic and leave more relaxed and less symptomatic.
So, in summary, for the structural and neurological reasons I have briefly discussed, I think it is important to examine and appropriately adjust, support, and rehab the feet, knees, and hips for our spinal procedures to be more effective and last longer.
Dr. Mark Charrette is a 1980 summa cum laude graduate of Palmer College of Chiropractic and a former All-American swimmer. He is a frequent guest speaker at chiropractic colleges and has taught over 2,200 seminars worldwide on extremity adjusting, biomechanics, and spinal adjusting techniques. He has authored a book on extremity adjusting and produced an instructional video series. His lively seminars emphasize a practical, hands-on approach. As a Foot Levelers Speakers Bureau member, he travels the country sharing his knowledge and insights. See continuing education seminars with Dr. Charrette and other Foot Levelers Speakers at footlevelers.com/continuing-education-seminars.
References
1. Furman ME, Gallo FP. The neurophysics of human behavior: explorations at the interface of brain, mind, behavior, and information. 1st ed. Boca Raton: CRC Press; 2000. doi.org/10.1201/9781420040432
2. Guyton A. Basic neuroscience. 2nd ed. Philadelphia: WB Saunders; 1991.
3. Magee DJ. Orthopedic physical assessment. 2nd ed. Philadelphia: WB Saunders; 1992. 459.
4. Langer S. (1976) Structural Leg Syndrome. JAPA66:723.
5. Huang CK, Kitaoka HB, An KN, Chao EY. Biomechanical evaluation of longitudinal arch stability. Foot Ankle. 1993 JulAug;14(6):353-7. doi: 10.1177/107110079301400609. PMID: 8406252.
6. Basmajian JV, Stecko G. The role of muscles in arch support of the foot. J Bone Joint SurgAm. 1963 Sep;45:1184-90. PMID: 14077983.
7. Cambron JA, Dexheimer JM, Duarte M, Freels S. Shoe orthotics for the treatment of chronic low back pain: a randomized controlled trial. Arch Phys Med Rehabil. 2017 Sep;98(9): 1752-1762. doi: 10.1016/j. apmr.2017.03.028. Epub 2017 Apr 30. PMID: 28465224.
8. Kent, C. A four-dimensional model of vertebral subluxation. Dynamic Chiropractic [Internet], 2011 Jan. Available from: https://dynamicchiropractic.co...
9. Smith HS, Hou Q. The peripheral muscarinic dysafferentation (PMD) theory of neuropathic pain. Journal of Neuropathic Pain & Symptom Palliation. 2005; 1(2): 19-26. doi.org/10.3109/J426v01n02_04 "
10. Kabell J. Sympathetically maintained pain. In: Willis W. ed. Hyperalgesia and allodynia. New York: Raven Press; 1992.
11. Nansel D, Szlazak M. Somatic dysfunction and the phenomenon of visceral disease simulation: a probable explanation for the apparent effectiveness of somatic therapy in patients presumed to be suffering from true visceral disease. J Manipulative Physiol Then 1995 Jul-Aug; 18(6):379-97. PMID: 7595111.
12. Slosberg M. Effects of altered afferent articular input on sensation, proprioception, muscle tone and sympathetic reflex responses. J Manipulative Physiol Ther. 1988 Oct;ll(5):400-8. PMID: 3069947.
